How long would your items be without refrigeration? Could you store them in the fridge at work, keeping them cool for all but your commute times?

Fruit is a natural for traveling well; most are already in an ideal serving size and self-contained. Citrus fruits might be a bit of a pain to peel and eat, but apples, pears, and fruits with pits all travel fairly well and leave no rinds to dispose of.

If you have access to a fridge throughout much of your day, pre-cut raw vegetables are another good choice. Carrots and other sliced vegetables can get a little dessicated throughout the day if not refrigerated, but if you can stick them in the office fridge, you're golden.

Sticks of string cheese keep and travel well. Because of their hardy packaging, they don't "sweat" the way other unrefrigerated cheeses might.

If your plan allows them, nuts are another really travel-friendly option. They're pretty calorie-dense, but eating just a small handful is often enough to stave off hunger and leave you feeling satiated with your snack.

Dried stuff is designed to last for weeks or months. Jerky and dried fruits will keep forever. The one danger involved with them is that it's easy to forget how dense they are; each thin little apple chip packs the same caloric punch as a wedge of a fresh apple, so watch your portions if you don't want to wind up eating five apples as a snack.